A McLaren Senna couldn’t quite reach its advertised top speed at the Johnny Bohmer proving grounds.
Last time a McLaren was at the Johnny Bohmer Proving Grounds in sunny West Palm Beach, Florida, we found out that the 720S is actually faster than McLaren says it is. The 720S is advertised as having a top speed of 212 mph, but Florida is so agreeable to the car’s temperament that it managed to reach a top speed of 215 mph.
So we have high hopes for the McLaren Senna, which features the same 4.0-L twin-turbo V6 power plant but tuned to produce 789 horses of thrust. Zero to sixty is roughly the same at just 2.7 seconds, with an advertised top speed of 208 mph.
Why, then, is the Senna slower than the 720S? That all has to do with drag. At just 155 mph, the Senna produces as much as 1,750 lbs of downforce, which is almost enough for the car to drive upside down. It’s massive rear wing and various aerodynamic body elements combine to keep the Senna stuck to the concrete like glue as it tears through a race track.
So we weren’t quite all that surprised to see the Senna struggle when it comes to topping out at speeds faster than the 720S.
As expected, the Senna can rocket to roughly 190 mph without much issue, but getting past 200 looked like an enormous struggle. Eventually, we see the car top out at 204 mph, but just barely. The speedo kept dipping back to 203 mph, so we’re pretty convinced that’s all the Senna’s engine could give us.
So why the big discrepancy? Well, it was a bit hotter during the test than on previous Bohmer videos, topping out at 88 degrees F (and probably over 100 with the humidity) that day. But the real culprit is the car’s downforce. In their quest to make the Senna the ultimate track car, they sacrificed the Senna’s top speed.
Still, it’s surprising that McLaren would get their speed estimate off by 4 mph. Or maybe not--after all, the 720S was 3 mph faster than advertised.